LITTLE BAG DYNAMICS

In the quark bag theory of baryons, pions are coupled to the bag surface in such a way as to make the axial-vector current continuous across the boundary. Inside the bag, the axial-vector current is carried by the quarks; outside by the gradient of the pion field. The discontinuity of the pion field at the bag surface provides a source, of definite strength, of pions there. From this source function a pion current is calculated in a straightforward fashion. Dynamics involving pion emission or absorption is then prescibed. As an example of such dynamics, the decay width of the Δ(1232) isobar is calculated, and found to be ΓΔ = [ 3j1(kπR) kπR]2 MeV, where kπ is the momentum of the emitted pion kπ = 228MeV. This calculated width is not far from the empirical value as long as the bag radius R is less than ≈ 0.5 fm. © 1979.